Residents in Lake County and surrounding areas are being alerted by health officials to an outbreak of pertussis, commonly known as whooping cough.
Officials reported 138 cases -- up from 91 cases about three weeks ago -- of the highly communicable disease had been reported as of Thursday. It is the highest in Lake County in three years.
Cases are being found in people of varying ages, especially children and young teenagers, including those who previously had a vaccination for the illness.
"It's a false notion to assume that pertussis is a mild disease limited only to babies, toddlers, and unvaccinated people," according to Irene Pierce, executive director of the Lake County Health Department.
The alert was issued because of an increase in the number of reported cases.
"Respiratory illnesses usually go up this time of year because people are indoors and coughing on each other," said Leslie Piotrowski, spokeswoman for the health department.
The highest number of reported cases in Lake County was 153 in 2004, she said. A change in the vaccine that year made it less effective.
Reports have come from throughout Lake County, although clusters have been noted at the School of St. Mary Upper Grade Center in Lake Forest and Carl Sandburg Middle School in Mundelein. As of a few days ago, 10 cases had been reported at each facility.
Carl Sandburg, which has 595 students, reported four cases as of mid-November. Health department information on whooping cough in English and Spanish again will be sent home as a reminder to parents, Principal Mark Pilut said.
The situation is being monitored but it is considered to be under control, he added.
Anyone with a long-lasting severe cough that tends to be worse at night and sounds different from a typical upper respiratory cough should see a doctor. Over-the-counter medications don't work in treating whooping cough.
The disease can last several months. Symptoms usually appear five to 10 days after exposure but can take as long as three weeks. The first symptoms are similar to those of a common cold but the cough becomes severe and often progresses to spasms that can result in vomiting or the high-pitched "whoop" sound. Coughing can last as long as 10 weeks.
Health officials said the disease can be prevented with a vaccine. Those aged 11 to 64 and those 65 and over who are caregivers for young children should get a vaccine booster.
Anyone who has the illness confirmed by a medical provider should stay home from work or school during the first five days of treatment.
Call (847) 377-8130 or visit http://www.lakecountyil.gov.